Table 4. Summary of the Bioprocess Optimization Strategies Employed for Enhancement of α-Tocopherol in In Vitro Cultures.
| species | culture type | strategy employed | enhancement in tocopherol levels (yield/titer/productivity of α-tocopherol)a | control with which yield enhancement was compared | |
|---|---|---|---|---|---|
| Helianthus annuus | callus157 | media optimization | naphthaleneacetic acid (0.5 mg L–1) and 6-benzylaminopurine (0.5 mg L–1) | 2.2-fold (15 μg g–1 FW) | callus grown in Murashige and Skoog basal medium |
| callus157 | media optimization | synergy of naphthaleneacetic acid (0.5 mg L–1), 6-benzylaminopurine (0.5 mg L–1), casamino acids (0.1% w/v), and myo-inositol (0.1% w/v) | 3.6-fold (19 μg g–1 FW) | callus grown in Murashige and Skoog basal medium + naphthaleneacetic acid (0.5 mg L–1) and 6-benzylaminopurine (0.5 mg L–1) | |
| cell suspension157 | media optimization | casamino acids (0.1% w/v) and myo-inositol (0.1% w/v) | 28% (13 μg g–1 FW) | suspension culture grown in absence of casamino acids and myo-inositol | |
| cell suspension154 | photomixotrophic conditions | white fluorescent light (125 μmol photons m–2 s–1) with reduced sucrose (3 g L–1) concentration | 4-fold (18 μg g–1 FW) | culture grown in white light with 30 g L–1 sucrose concentration | |
| cell suspension156 | photomixotrophic conditions | light (125 μmol m–2 s–1) + sucrose (15 g L–1) | 230% (77 μg g–1 DW) | culture grown in heterotrophic conditions (without light) | |
| cell suspension164 | elicitor addition | 72 h treatment of jasmonic acid (5 μM) | 49% (11 μg g–1 FW) | culture grown in absence of elicitor | |
| cell suspension157 | precursor addition | 72 h treatment of homogentisic acid (100 mg L–1) | 30% (16 μg g–1 FW) | culture grown in absence of precursor | |
| cell suspension15 | elicitor exposure | hypoxic conditions | 1.4-fold (140% concentration of control) | culture grown in normal conditions | |
| cell suspension162 | elicitor addition | 48 h treatment sodium chloride (50 mg L–1) | 2.3-fold (46 μg L–1 d–1) | culture grown in absence of elicitor | |
| hairy roots158 | elicitor exposure | 32 h treatment reactive red dye (110 mg L–1) | up to a maximum of 49 μg g–1 DW | ||
| hairy roots158 | light treatment | 16/8 light/dark conditions | 2-fold | culture grown in dark conditions | |
| safflower | callus151 | media optimization | revised tobacco medium with indole-3-butyric acid (2 ppm), kinetin (0.1 ppm), and casamino acid (0.1% w/v) | 5-fold (38 μg g–1 DW) | callus grown in Murashige and Skoog medium with 2,4-D and kinetin |
| suspension culture153 | light treatment | 7000 lx and 16/8 light/dark conditions | 3.3 times (340 μg g–1 DW) | culture grown in dark with optimal media conditions151 | |
| callus176 | media optimization | casein (0.1% w/v) with 2,4-dichlorophenoxy acetic acid (0.3 mg L–1) and 6-benzylaminopurine (1.8 mg L–1) | up to 4.17 μg g–1 FW | culture without addition of casein | |
| cell suspension152 | synergy of media and aeration rate | 8 mg O2 L–1 + addition of conditioning factor | up to 0.09 mg g–1 DW | higher than parent safflower seeds | |
| cell suspension153 | precursor addition | phytol (100 mg L–1) | 5 times (1.4 mg g–1 DW) | culture without addition of precursor | |
| cell suspension171 | elicitor addition | 4 week treatment of dried fungal mats of Trametes versicolor (50 mg L–1) | 12.7-fold (2 mg g–1 FW) | culture without addition of elicitor | |
| cell suspension171 | elicitor addition | 4 week treatment of sodium chloride (50–70 mg L–1) | 1.24-fold (200 μg g–1 FW) | culture without addition of elicitor | |
| callus175 | elicitor exposure | 10 min exposure to UV -C radiation | positive effect | culture without exposure to elicitor | |
| Vitis vinifera | cell suspension173 | elicitor addition | 6 day treatment of cadmium chloride (1 mM) | 1.7-fold (1.45 μg g–1 DW) | culture without addition of elicitor |
| Rosa damascene | callus159 | precursor addition | 21 day treatment of phenyl alanine (100 μM) in dark light | 2-fold (11 ppm) | culture without addition of precursor |
| callus159 | elicitor addition | 21 day treatment of methyl jasmonate (5 μM) in dark light | 4-fold (20 ppm) | culture without addition of elicitor | |
| Argania spinosa | cell suspension170 | precursor addition | 10 day treatment of tyrosine (276 μM) | 2-fold (0.6 mg g–1 DW) | culture without addition of precursor |
| cell suspension170 | elicitor addition | 10 day treatment of titanium dioxide (5 ppm) and tyrosine (276 μM) | 4.5 times (2.7 mg g–1 DW) | culture without addition of elicitor | |
| cell suspension170 | elicitor addition | 10 day treatment of silicon dioxide (5 ppm) and tyrosine (276 μM) | 4.7 times (2.8 mg g–1 DW) | culture without addition of elicitor | |
| Amaranthus caudatus | callus163 | elicitor addition | 72 h treatment of methyl jasmonate (100 μM) | 5-fold (11 μg g–1 DW) | culture without addition of elicitor |
| Arabidopsis | cell suspension164 | elicitor addition | 72 h treatment of jasmonic acid (5 μM) | 66% (9 μg g–1 FW) | culture without addition of elicitor |
| cell suspension167 | exposure to elicitation | anoxic stress in shake flask without mixing for 24 h | 62% (12 μg g–1 FW) | culture without exposure to elicitation | |
| cell suspension167 | exposure to elicitation | 4 h anoxic stress in stirred tank reactor by nitrogen sparging | 14% (8 μg g–1 FW) | culture without exposure to elicitation | |
| Dacus carota | cell suspension168 | elicitor addition | 21 day treatment of cyclodextrin (10–70 mM) | up to a maximum of 172 μg g–1 DW | |
| Cucumis sativus | cell suspension172 | elicitor addition | 72 h treatment of sodium chloride (150 mM) | 50% (4 μg g–1 protein) | culture without exposure to elicitation |
a
FW, fresh weight; DW, dry weight.